Life Sciences Commons^™

Loss Of A Foundation Species, Eastern Hemlock (Tsuga Canadensis), May Lead To Biotic Homogenization Of Fungal Communities And Altered Bacterial Abundance In The Forest Floor, Aliza Fassler, Jesse Bellemare, Danielle D. Ignace

Biological Sciences: Faculty Publications

Tsuga canadensis (Eastern Hemlock) is a key forest foundation species that is currently declining across the eastern US due to attack by exotic insect species, primarily Adelges tsugae (Hemlock Woolly Adelgid). In the northeastern US, declining Eastern Hemlock stands are typically replaced by fast-growing deciduous Betula lenta (Black Birch) trees, altering ecosystem processes and ecological communities. In this study, we used an approach that substituted space for time to explore how the forest floor's soil organic horizon, macrofungal communities, and bacterial abundance might be altered following Eastern Hemlock replacement by Black Birch. We compared intact, mature Eastern Hemlock forest plots …

The Potential For Indirect Negative Effects Of Exotic Insect Species On A Liverwort, Bazzania Trilobata (Lepidoziaceae), Mediated By The Decline Of A Foundation Tree Species, Tsuga Canadensis (Pinaceae), Michelle R. Jackson, Jesse Bellemare

Biological Sciences: Faculty Publications

In many ecological communities, the effects of exotic species are likely to extend beyond their direct interactions with natives, due to indirect effects. This dynamic might be particularly consequential in cases where invasive insects or other exotic herbivores target foundation plant species in the communities they invade. In this study at a site in western Massachusetts, we used experimental transplants to gauge the potential effects of a decline in the evergreen conifer Tsuga canadensis due to ongoing spread of two exotic insect pests on a liverwort, Bazzania trilobata, whose distribution is closely linked to dense stands of this conifer in …

Climate Change, Managed Relocation, And The Risk Of Intra-Continental Plant Invasions: A Theoretical And Empirical Exploration Relative To The Flora Of New England, Jesse Bellemare, Bryan Connolly, Dov F. Sax

Biological Sciences: Faculty Publications

The high rate of anthropogenic climate change projected for coming decades and evidence of low migration ability for many species have led researchers to warn of a looming extinction crisis. This threat is expected to be most acute for small-ranged endemic species, which could see novel climatic conditions develop rapidly across the entirety of their limited geographic ranges. To avoid extinctions, some conservationists have proposed that climateimperiled species might be candidates for "assisted colonization" or "managed relocation" to new regions, outside their historical ranges. One major concern related to managed relocation is the possibility that some relocated species could later …

Plants' Native Distributions Do Not Reflect Climatic Tolerance, Tierney Bocsi, Jenica M. Allen, Jesse Bellemare, John Kartesz, Misako Nishino, Bethany A. Bradley

Biological Sciences: Faculty Publications

Aim: Biogeographers have long known that plant species do not fully encompass their fundamental niche. Nonetheless, in practice, species distribution modelling assumes that plant distributions represent a reasonable approximation of their environmental tolerance. For ecological forecasting, projections of habitat loss due to climate change assume that many species will be unable to tolerate climate conditions outside of those found within their current distributional ranges. We aim to test how well occurrences in the native range approximate the climatic conditions in which plant species can survive.

Location: Continental USA. Methods: We compared the climatic conditions between occurrences in the US native …

Horticultural Escape And Naturalization Of Magnolia Tripetala In Western Massachusetts: Biogeographic Context And Possible Relationship To Recent Climate Change, Jesse Bellemare, Claudia Deeg

Biological Sciences: Faculty Publications

No abstract provided.

Niche Syndromes, Species Extinction Risks, And Management Under Climate Change, Dov F. Sax, Regan Early, Jesse Bellemare

Biological Sciences: Faculty Publications

The current distributions of species are often assumed to correspond with the total set of environmental conditions under which species can persist. When this assumption is incorrect, extinction risk estimated from species distribution models can be misleading. The degree to which species can tolerate or even thrive under conditions found beyond their current distributions alters extinction risks, time lags in realizing those risks, and the usefulness of alternative management strategies. To inform these issues, we propose a conceptual framework within which empirical data could be used to generate hypotheses regarding the realized, fundamental, and 'tolerance' niche of species. Although these …

Homogenization Of Forest Plant Communities And Weakening Of Species-Environment Relationships Via Agricultural Land Use, Mark Vellend, Kris Verheyen, Kathryn M. Flinn, Hans Jacquemyn, Annette Kolb, Hans Van Calster, George Peterken, Bente Jessen Graae, Jesse Bellemare, Olivier Honnay, Jörg Brunet, Monika Wulf, Fritz Gerhardt, Martin Hermy

Biological Sciences: Faculty Publications

Disturbance may cause community composition across sites to become more or less homogenous, depending on the importance of different processes involved in community assembly. In north-eastern North America and Europe local (alpha) diversity of forest plants is lower in forests growing on former agricultural fields (recent forests) than in older (ancient) forests, but little is known about the influence of land-use history on the degree of compositional differentiation among sites (beta diversity). Here we analyse data from 1446 sites in ancient and recent forests across 11 different landscapes in north-eastern North America and Europe to demonstrate decreases in beta diversity …

Rich Mesic Forests: Edaphic And Physiographic Drivers Of Community Variation In Western Massachusetts, J. Bellemare, G. Motzkin, D. R. Foster

Biological Sciences: Faculty Publications

Rich Mesic Forest, a Northeastern variant of the species-rich Mixed Mesophytic Forest association of eastern North America, is an Acer saccharum-dominated forest type typically associated with calcareous bedrock and nutrient-rich, mull soils. Rich Mesic Forest (RMF) is a priority for conservation in the Northeast due to its limited areal extent, high plant species richness, and numerous rare taxa, yet the community characteristics and environmental correlates of this forest type are incompletely understood. This study undertook a quantitative classification of RMF of the northeastern edge of the Berkshire Plateau in western Massachusetts. Cluster analysis of data from ten sites identified two …